As a configuration of a stator of a rotary electric machine, its iron core may be integrally formed in a circular tube shape. In this configuration, since the inner circumference of the stator can be formed in a substantially exact circular shape, there is an advantage that cogging torque due to permeance pulsation at a gap portion of a motor hardly occurs. On the other hand, there are the following problems. Since the iron core needs to be formed in a circular shape, particularly, in the case of using a laminated iron core, materials of the inner and outer circumferential portions cannot be utilized, and therefore the material yield is low. In addition, since a conductive wire is wound in a narrow slot portion on the inner circumference, the occupancy rate of the conductive wire decreases.
In order to solve the above problems, a configuration has been proposed that a foldable joint portion is provided on a stator so that the stator can be linearly expanded (for example, see Patent Document 1).
This configuration has an advantage that the material yield is improved and winding is facilitated, as compared to the conventional configuration of integrally forming an iron core in a circular tube shape.
In addition, a configuration has been proposed that a stator is formed by joining L pieces of divided iron cores (L is a stator tooth number) for respective teeth (for example, see Patent Document 2).
This configuration has an advantage that the material yield is improved and winding is facilitated, as compared to the conventional configuration of integrally forming an iron core in a circular tube shape.